Generally, catalyst carriers have shapes such that cells thereof are arranged in a honeycomb shape. A mold for producing such catalyst carriers is an extrusion mold. That is, material is injected into one side of the mold by pressing, so that a product is formed while being discharged through the opposite side of the mold.
In conventional arts, most cells have square or hexagonal cross-sections. Molds for producing catalyst carriers have been manufactured by grinding machining or electric discharge machining. Therefore, due to limits of machining accuracy, there is a difficulty in manufacturing a mold which is able to produce catalyst carriers having cell density of approximately 900 cpsi (cells per square inch) and a web having a thickness of approximately 2.5 mil (mili-inches).